Redescriptions and small subunit ribosomal RNA (SSU rRNA) gene sequence analyses of two marine oligotrich ciliates, Strombidium sulcatum and S. stylifer (Ciliophora, Oligotrichia)

Abstract

As Strombidium sulcatum, the type species of the genus Strombidium, has been frequently reported from various localities and habitats in the world, its taxonomy, behavior, physiology and other biological aspects are relatively well informed. However, more detailed information on its live cell and infraciliature is still necessary because of its morphological variation in the ecological difference. Korean population of S. sulcatum was sampled from tidal pools in Yeosu and Sacheon where water temperature of 12-14 ℃ and salinity of 34 psu were recorded. The presence/absence of an anterior bump-like protuberance is a morphological key to be distinguished with a similar species, S. inclinatum. Korean population had a protuberance in vivo only and no difference in protargol preparations compared with S. inclinatum. SSU rRNA analysis did not show a significant difference (<1%) between S. sulcatum and S. inclinatum gene sequences. Considering the level of SSU rRNA-based operational taxonomic units (OTUs) for the delimitation within oligotrichs and choreotrichs, S. sulcatum and S. inclinatum can be conversed in a monospecies. Another Strombidium species from tidal pools in Wan-do and Goseong, S. stylifer was collected and then small subunit rRNA sequences as well as its morphological description and ecological information were provided as the first record in Korea.rmed. However, more detailed information on its live cell and infraciliature is still necessary because of its morphological variation in the ecological difference. Korean population of S. sulcatum was sampled from tidal pools in Yeosu and Sacheon where water temperature of 12-14 ℃ and salinity of 34 psu were recorded. The presence/absence of an anterior bump-like protuberance is a morphological key to be distinguished with a similar species, S. inclinatum. Korean population had a protuberance in vivo only and no difference in protargol preparations compared with S. inclina